#include <vector>
#include <fstream>

class big_int
{
private:
   std :: vector <int> digits;
   static const int base = 1000000000;
   static const int base_lenght = 9;
   
private:
   int compare_to(const big_int&, int) const;
   void cut_zeros();
   int find_quot(const big_int&, int) const;
 
public:
   big_int(std :: string);
   big_int multiply (int&) const;
   big_int subtract(const big_int&, int) const;
   std::pair<big_int, big_int> divide(const big_int&) const;

   big_int operator *(int&) const;
   friend std::ofstream& operator <<(std::ofstream&, const big_int&);
};